Previously it has been described that the quality of the calcium-containing compound as well as the method for preparation of a pharmaceutical composition containing the calcium-containing compound are of great importance in order to obtain acceptable taste and mouth-feel of a chewable tablet (WO 00/28973). In contrast to WO 00/28973 the method according to the invention does not employ a step of binding the particles together by a wet granulation process, which means that the method according to the invention advantageously can be employed when it is desired to incorporate substances that are sensitive towards humidity. An example of such a substance is vitamin D that often is included together with a calcium salt in a pharmaceutically dosage form. The present invention provides a simple and cost-effective alternative method to obtain such a dosage form without the need of a step e.g. involving wet granulation.
To this end, the present inventors have previously found that roller compaction is a suitable method for the preparation of pre-compacted calcium-containing material comprising a regularly shaped calcium-containing compound and a sugar alcohol. However, not all sugar alcohols are equally suitable. Thus, sugar alcohols having a suitable microstructure were favourable to use. An especially suitable quality was sorbitol having a specific small mean particle size of below 50 μm. These findings are described in the co-pending PCT application with application No. PCT/DK2005/000338. U.S. Pat. No. 6,475,510 describes a process for manufacturing bite-dispersion tablets. In Example 6 calcium carbonate is mentioned. However, there is no specification of the quality of calcium carbonate employed and, moreover, a waxy material like e.g. Precirol has been employed. In a material according to the present invention, there is no need to add such a waxy material due to the fact that the quality of the calcium-containing compound is carefully selected. Accordingly, in a specific embodiment, a material according to the present invention does not contain Precirol or any other waxy material as those mentioned in column 5, lines 31-39 of U.S. Pat. No. 6,475,510 (i.e. mono-, di- or tri-C10-C30 aliphatic esters of glycerol, especially glycerol palmito-stearate or glyceryl behenate; the high molecular weight (C10-30) straight chain aliphatic alcohols, such as stearyl alcohol or cetyl alcohol; and mixtures of high molecular weight aliphatic acids and esters; or combinations thereof. Especially, the waxy material is stearyl alcohol or cetyl alcohol, or is glycerol palmito stearate or glyceryl behenate.)
However, there is a need for using roller compaction for other calcium-containing compounds as those of regular shape and, furthermore, there is a need for using other kinds of sugar alcohols as those having binding properties and a micro-structure. Especially, the use of xylitol is of major importance as xylitol has positive impact on the sensoric properties of the end product (e.g. a chewing tablet).